
  package com.ninth.filter;

  import java.io.IOException;

  import javax.servlet.Filter;
  import javax.servlet.FilterChain;
  import javax.servlet.FilterConfig;
  import javax.servlet.ServletException;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.servlet.annotation.WebFilter;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import javax.servlet.http.HttpSession;

  /**
   * 登录拦截器，
   * 拦截器名LoginFilter
   * 拦截的地址：/admin/*  表示后台的所有请求
   * 
   *
   */
  @WebFilter(filterName="LoginFilter",urlPatterns="/admin/*")
  public class LoginFilter implements Filter{
    

    /**
     * 执行过滤
     */
      public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
        throws IOException, ServletException {
      HttpServletRequest servletRequest = (HttpServletRequest) request;
      HttpServletResponse servletResponse = (HttpServletResponse) response;
      HttpSession session = servletRequest.getSession();

      String path = servletRequest.getRequestURI();
      System.out.println("请求地址"+path);
      
      // 登陆页面无需过滤
      if (path.indexOf("/login.jsp") > -1 || path.indexOf("/LoginServletAdmin") > -1) {
        chain.doFilter(servletRequest, servletResponse);//放行
        System.out.println("登录页面和登录请求，放行！");
        return;
      }
      
      String user = (String) session.getAttribute("userName");
      // 判断如果没有取到员工信息,就跳转到登陆页面
      if (user == null || "".equals(user)) {
        System.out.println("session未存储用户信息,跳转到登陆页面");
        System.out.println(user);
        servletResponse.sendRedirect("../admin/login.jsp");
      } else {
        // 已经登陆,继续此次请求
        chain.doFilter(request, response);
        System.out.println("已经登陆,放行");
      }
    }

      
    @Override
    public void destroy() {
      System.out.println("销毁时执行");
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
      System.out.println("初始化时执行");
    }


  }
